Field of Technology
The embodiments herein relate to a fringe field liquid crystal display (LCD) device, and more particularly, to a fringe field LCD device which can enhance color purity, and prevent the occurrence of flicker.
Discussion of the Related Art
LCD devices, which are widely used as a type of display device, are largely categorized into lateral electric field LCD devices, vertical electric field LCD devices, and fringe field LCD devices depending on a direction of an electric field which is applied for controlling alignment of liquid crystal. In fringe field LCD devices, one of a common electrode and a pixel electrode is flatly formed in a pixel area, and the other electrode is formed as a slit type with a protective layer therebetween. The fringe field LCD devices enhance an aperture ratio in comparison with the lateral electric field LCD devices, and realize a wide viewing angle in comparison with the vertical electric field LCD devices. Accordingly, the fringe field LCD devices are being applied to various electronic devices.
As the demand for high-definition display devices such as ultra high definition (UHD) display devices increases, it is required to solve problems of resolution, light transmittance, and power consumption in high-definition LCD devices. To solve the problems, various pixel structures applied to LCD devices are being developed.
FIG. 1A is a view illustrating a pixel structure in a related art LCD device having a red, green, blue (RGB) stripe structure, and FIG. 1B is a view illustrating a pixel structure in a related art LCD device having an red, green, blue, and white (RGBW) quad structure.
In a related art RGB stripe structure, as illustrated in FIG. 1A, one unit pixel area is defined by three adjacent pixel areas that respectively emit red (R) light, green (G) light, and blue (B) light. Unlike organic light emitting display devices, LCD devices need a separate light source, and light emitted from the light source passes through liquid crystal, and passes through a color filter included in each pixel to realize a color.
Therefore, in the RGB stripe structure, a plurality of pixel areas and color filters which display the same color are formed as a stripe type on an arbitrary column or row. On the other hand, in the RGBW quad structure, one unit pixel area is defined by two adjacent pixel areas.
For example, as illustrated in FIG. 1B, one unit pixel area including a R pixel area and a G pixel area is provided, and each of four unit pixel areas which are upward, downward, left, and right adjacent to the one unit pixel area includes a B pixel area and a W pixel area in which a separate color filter is not formed. Light emitted from the light source is irradiated onto a screen through the W pixel area without passing through the W pixel area, and thus, a brighter screen than the related art RGB stripe structure is realized, and light transmittance is improved.
However, in the related art RGBW quad structure, as illustrated in FIG. 1B, all pixel areas are designed to have the same size. Here, the whole light transmittance increases compared to the related art RGB stripe structure, but R, G, and B pure color luminance and color coordinates are changed. That is, whole luminance is increased by the W pixel area, but since an area of the W pixel area is added, areas of RGB pixel areas are reduced, causing a reduction in luminance of colors such as R, G, and B. For this reason, in the related art RGBW quad structure, an imbalance of luminance is caused by a color, causing a change in color coordinates.